function active_2tab(tab_b){
	if(tab_b=="tab_b1"){
		document.getElementById("tab_b1").style.display='block';		
		document.getElementById("menu_b1").className='tab_ac';		
	}
	else
	{
		document.getElementById("tab_b1").style.display='none';		
		document.getElementById("menu_b1").className='tab';			
	}
	if(tab_b=="tab_b2"){
		document.getElementById("tab_b2").style.display='block';		
		document.getElementById("menu_b2").className='tab_ac';		
	}
	else
	{
		document.getElementById("tab_b2").style.display='none';		
		document.getElementById("menu_b2").className='tab';			
	}
}